Somedays ago I installed Vista for the first time at my home desktop (I was very worried about the performance of this OS, so I took a long time to give it a try) and because of my disattention I erased my MBR, so my good old grub startup screen no longer appeared.
I couldn’t boot from my Kubuntu anymore ( I prefer KDE rather than Gnome 🙂 ). So, I googled a little bit and found at the Ubuntu forum how to restore grub from a Ubuntu live cd. I restored it with some steps and all went fine! I hope you enjoy this tip!